Maybe, but let's look at the big picture. Next Gen as a group continues to rise in an overall steady and consistent manner. Compare Next Genners (born 1994 or later) in the top 50 now to a year ago.
2017, before USO:
6 Zverev
17 Kyrgios
20 Pouille
29 Khachanov
42 Edmund
47 Chung
(with Donaldson, Rublev, Medvedev just outside top 50, Coric, Shapo, Tiafoe, Escobedo, and Djere in top 100)
2018, now (before USO):
4 Zverev
15 Tsitsipas
16 Edmund
17 Pouille
20 Coric
23 Chung
26 Khachanov
28 Shapovalov
30 Kyrgios
36 Medvedev
38 Rublev
42 Jarry
44 Tiafoe
45 de Minaur
(with Berretini, Fritz, McDonald, and Donaldson also in top 100)
That is from 6 to 14 players in top 50 (or 12% to 28%), and from 3 to 5 in top 20 (15% to 25%).
Some players have floundered a bit and/or held relatively steady: Kyrgios, Pouille, Khachanov, Zverev.
But a lot have risen substantially in the rankings: Tsitsipas, Edmund, Coric, Chung, Shapo, Medvedev, Rublev, Jarry, Tiafoe, de Minaur, Berretini, etc.
To play Devil's Advocate, Next Gen hasn't really been winning more titles. I just scanned both lists and they seem similar. But the overall performance has improved substantially. Their time is coming.